This invention relates generally to manufacturing machines and particularly to those having a table for supporting a work-piece and having a spindle operable to move tools down and up for drilling, milling, grinding, boring, reaming or other means of treating the work-piece. Modern machine shops almost inevitably have a computer numerically-controlled (CNC) milling machine or a similar machine. Because of the cost of CNC machines, it is important for purchasers of such equipment to be as conservative as possible in regard to accessories or extra features which are available for such machines at extra cost.
One of the essential steps in a work-piece treating operation is to be able to relate the working part of a tool to a dimension to be achieved on a work-piece and to the Z axis travel of the tool holding portion of the machine. Also, it is essential to be establishing a reference of the tool relative to the work-piece without damage to either of them. The present invention is addressed to meet this need.